Tofu coagulant producing apparatus and soymilk coagulation machine comprising the same

ABSTRACT

An apparatus for producing tofu coagulant, comprising: a liquid food oil pumping pathway H 1  from a liquid food oil tank T 1  by a metering pump P 1 ; a mineral salt solution pumping pathway H 2  from a mineral salt solution tank T 2  by another metering pump P 2 ; an emulsion dispersion machine M 1  for stirring the liquid food oil with the mineral salt solution to an emulsification phase; wherein the liquid food oil pumping pathway H 1  is connected with the mineral salt solution pumping pathway H 2 , and the mineral salt solution is added predetermined ratio for producing the tofu coagulant, wherein the water phase and the oil phase are stirred and mixed to W/O type (water in oil type) emulsion (without emulsifier).

TECHNICAL FIELD

The present invention relates to a tofu coagulant producing apparatus and soymilk coagulation machine comprising the tofu coagulant producing apparatus without emulsifier.

BACKGROUND ART

A mineral salt such a magnesium chloride (called “Nigari” in Japan) and a calcium chloride which working as tofu coagulant and used for producing tofu. And a glucono-δ-lactone that coagulating component is gluconic acid working as tofu coagulant and used for producing Tofu. It is skilful making a high quality tofu such a fine texture, a good touch with teeth and tongue, and a good taste. Particularly magnesium chloride and gluconic acid are very fast reaction rate with soymilk, and difficult to produce the high quality tofu constantly, shows in patent document 4 (JP 3553690B1). Thus, fat and emulsifier are mixed in magnesium chloride solution for making emulsification phase as water in oil (W/O) type, and which coagulant emulsion is commercially available, for example. And, a tofu coagulant which is comprised magnesium chloride, polyglycerol esters of fatty acids as emulsifier, and diglyceride, is disclosed in patent document 2 (JP 2908633B1). Diglyceride (DG) and Diacylglycerol (DAG) are same. And, a tofu coagulant which is comprising mineral salt coagulant, polyglycerol esters of fatty acids, and fat, is disclosed in patent document 3 (JP 2912249B1).

As above commercial emulsifier tofu coagulant comprises Nigari, it having a good slow-acting character and which is used manufacturing tofu products at high temperature solidification and popularized. The commercial emulsifier tofu coagulant is used preferable for mass production scale at tofu factory, because it induce stable product quality, low loss, and high working-efficiency. However, some consumers feel a peculiar flavor that is different to original tofu flavor, and increasing a uniform flavor of tofu products, losing distinctive regional production, same character by different manufacturers. Moreover, the commercial emulsifier tofu coagulant is 5 or 6 times more expensive than normal Nigari. The occasion of the recent economic downturn, rising fuel cost and soybeans cost and, wholesale price down pressure has been forced, in addition have to use expensive tofu coagulant, thus tofu manufacturer's economic burden that more and more. For reducing tofu costs, so tofu manufacturer yearn doesn't use the expensive tofu coagulant as possible and to provide consistent high-quality tofu production. Further more, the commercial emulsifier tofu coagulant including synthetic emulsifiers and stabilizers, thus it having a good slow-acting character, but, it is necessary to use with high-power emulsifying dispersion machine for good dispersion. Therefore, sometimes dispersion level of the commercial emulsifier tofu coagulant is low and tofu products lost or amount of the commercial emulsifier tofu coagulant is much and tofu product deteriorated during distribution process. In recent years, the global boom in Japanese food, tofu is a situation where demand is growing by the principle natural food, especially vegetarian. Especially in the West has increased the demand for organic products, processed food in Japan is about 60% organic soy milk and tofu products that situation would. Future, tofu products, consisting of natural raw materials are expected to continue to increase as the representative of the expected natural food without any synthetic chemical food additives.

The applicant herein issued and patent granted tofu manufacturing method patent document 1 (JP 3654623B1) which is given in the device configuration and do not use emulsifiers as additives. However, to enforce a narrow scope, selected by a combination of food fat and Nigari what kind of concentration and type, was not consistently high-quality tofu satisfy. For reducing the cost of W/O type emulsified coagulant emulsion, use less oil, and reduce the amount of aqueous phase, it is necessary to use higher concentrations of aqueous Nigari, for example. However, high concentrations Nigari, it can stabilize the product by increases the viscosity of the emulsion, but it is difficult to make optimal stable emulsified phase affected by heat such a friction heat, thus practical slow-acting character was hard to obtain. Nigari concentration in less than 2M, and inconvenient solution emulsified with fever and increased emulsion viscosity is less obvious.

Study to W/O type emulsion characteristic that is used salt water and processing oil and does not use emulsifiers as additive, is disclosed in related art document 2 and related art document 5. The processing oil comprises DAG more than 80%. But, those related art 2, 3 were not evaluated slow-acting character as tofu coagulant, and concentration of magnesium chloride solution is 0.5M or less, and it is not affected by heat such a friction heat. And it is evaluated that salt water phase and oil phase ratio is 1:1 only. Unit M is the molar concentration per liter of solution. Concentration of magnesium chloride solution that converted to magnesium chloride based on 06 water salt crystals of molecular weights approximately 203 is about 10% w/w, and the specific gravity is approximately 1.036. If using coagulation of soymilk to dilute salt solution, the aqueous phase increases and it is necessary to increase the amount of fat, thus does not be economical. DAG is a fat which is same as conventional triacylglycerol (TAG). DAG is a fat component that is comprised a number of commercial vegetable oils such as olive oil, and DAG is the percent of ingredients that contain fat, is disclosed in related art document 6.

The applicant herein filed and publicated tofu coagulant and manufacturing method uses of the tofu coagulant patent document 6 (JP 2010-168533). The patent document 6 is shown in which is obtained stirred mineral salt solution with food fat including more than 1% of DAG, or which is stabilizing W/0 type emulsion after cooled and stirred for slow-acting.

And, an emulsification device for dressing is disclosed in patent document 7 (JP H11-196816A). Generally, dressing is an O/W type emulsion. And, an O/W type emulsion for Margarine or Chocolate which is not used emulsifier is disclosed in patent document 8 (JP 2006-254816B1). Generally, Margarine and Chocolate are solid food that are used food fat with high melting point and stabilizing crystallization of the food fat. A W/0 type emulsion which comprising artificially 1,2-DAG more than 50% in DAG is disclosed in patent document 9 (JP 4381362B1). But, related art document 7 is shown in which ratio of 1,2-DAG versus 1,3-DAG is 3:7 in natural fat.

PATENT DOCUMENT

-   Patent document 1 is JP 3654623B1 -   Patent document 2 is JP 2908633B1 -   Patent document 3 is JP 2912249B1 -   Patent document 4 is JP 3553690B1 -   Patent document 5 is JP 3853778B1 -   Patent document 6 is JP 2010-168533 -   Patent document 7 is JP H11-196816A -   Patent document 8 is JP 2006-254816B1 -   Patent document 9 is JP 4381362B1

LITERATURE

-   Related art document 1 is A. Tsuji, Solubilization and     emulsification technique, Engineering Library co., ltd, page 58-114,     Year 1976. -   Related art document 2 is A. Shimada and K. Ohashi, Effect of salt     type on the emulsifying Properties of water-in-oil emulsions     prepared with diacyglycerol without an emulsifier, School of Human     Life Sciences Showa Women's University, vol. 14, page 31-38, Year     2005. -   Related art document 3 is A. Shimada and K. Ohashi, Interfacial and     emulsifying properties of diacyglycerol, Food science technology     research, No. 9, page 142-147, Year 2003. -   Related art document 4 is M. Kimura, et al., Emulsifying properties     of various vegetable oils, Bioscience, Biotechnology, and     Biochemistry (Japan Society for Bioscience, Biotechnology, and     Agrochemistry) Z53-G223., vol. 58, page 1258-1261, Year 1994. -   Related art document 5 is K. Stigita, et al., Encyclopedia of Japan     foods, Ishiyaku Publishers, Inc., page 527-544, First edition, Year     2003. -   Related art document 6 is Riv. Ital. Grasse, La Rivista italiana     delle sostanze grasse, Vol. 69, page 443-447, Year 1992. -   Related art document 7 is, Interface handbook, N.T.N. co., ltd,     first edition, page 1096, Year 2001. -   Related art document 8 is, Handbook of oil chemistry, Maruzen co.,     ltd, fourth revised edition; page 10, Year 2001. -   Related art document 9 is, Handbook of oil chemistry, Maruzen co.,     ltd, third revised edition, page 148-149.

DISCLOSURE OF THE INVENTION Problems the Invention Intends to Solve

As above patent document 1, a milk solid (emulsion) is obtained which basis liquid oil such a soybean oil and thin magnesium chloride solution used by emulsion circulation means. And concentration of the magnesium chloride solution is about 1.8 M that converted to magnesium chloride based on 06 water salt is about 33% w/w, and the specific gravity is approximately 1.1. However, the milk solid will return to the original phase at few seconds, thus it is necessary uses the emulsion circulation means continuously during to use. So, the milk solid is easy to breakdown the emulsion cause of increasing viscosity and heating. Therefore, the milk solid is difficult to handle. The feed pump stator and rotor fitted as likely Mono-pump is caused re-aggregate the emulsification for their rubbing action. Moreover, in case of W/O ratio 1:1 that concentration of the magnesium chloride solution is 17% w/w and additive ratio for soymilk is 1.7 to 1.8 wt %, and in case of W/O ratio 2:1 that concentration of the magnesium chloride solution is 22% w/w and additive ratio for soymilk is 1.3 to 1.4 wt %. There is no emulsifier and use more oil, so the milk solid additive amount is much more in actual. Then, it is necessary to use large feed pump and tank, and material cost is increase by using food oil. Unless otherwise specified, “%” equal “weight percent”. And concentration of the magnesium chloride solution is magnesium chloride crystal on 06 water salt (MgCl₂ 6H₂O).

As above patent document 2 and 3, polyglycerol esters of fatty acids as emulsifier is slow-acting and flavor is getting worse when it amount is much. The polyglycerol esters of fatty acids is strong emulsifier and become uneven soymilk when strong circulation means unused. And in case of it happens that white speck remains in tofu, the speck stick on package film, and cloth does not easy to remove momen-tofu. Therefore, it is necessary to use a high-speed mixer and the mixer is over loaded working continuously. The other documents as above sited are not shown W/O type tofu coagulant producing apparatus or method without emulsifier.

The innovators herein developed tofu manufacturing method patent document 1 which is given in the device configuration and do not use emulsifiers as additives. In case of the method, it is necessary to keep emulsification state continuously by machine. But, it is difficult to make optimal stable emulsified phase affected by heat such a friction heat, thus practical slow-acting character was hard to obtain. Moreover, to keep emulsification state continuously by machine circulation, to increase temperature that is cause of braking the emulsified phase.

After that, the inventors herein studied hard, and found the manufacturing condition in which is obtained practical slow-acting character for satisfy to producing tofu constantly without emulsifier. In other words, do not use emulsifier as additive, and select a liquid food oil including DAG and a mineral salt solution, and control emulsified conditions, and then the tofu coagulant is obtained easily.

The object of the present invention is, therefore, to provide a tofu coagulant producing apparatus and soymilk coagulation machine comprising the tofu coagulant producing apparatus without emulsifier. The obtained tofu coagulant is used only liquid food oil with mineral salt solution, and it is not used expensive commercially available emulsifier. The tofu manufacturers use the obtained tofu coagulant and producing tofu with their original flavors constantly and economically. Moreover, the obtained tofus are imaged up as natural food and safety, easy, and high quality.

SUMMARY OF THE INVENTION

To accomplish the above object, the present invention provides an apparatus for producing tofu coagulant, comprising: a liquid food oil pumping pathway from a liquid food oil tank by a metering pump; a mineral salt solution pumping pathway from a mineral salt solution tank by another metering pump; an emulsion dispersion machine for stirring the liquid food oil with the mineral salt solution to an emulsification phase; wherein the liquid food oil pumping pathway is connected with the mineral salt solution pumping pathway, and the mineral salt solution is added predetermined ratio for producing the tofu coagulant, wherein the water phase and the oil phase are stirred and mixed to W/O type (water in oil type) emulsion (without emulsifier).

According to the present invention, the emulsion dispersion machine is continuous processing and each of the materials from metering pumps passing an emulsification chamber of the emulsion dispersion machine at one way passing when volume of the emulsion chamber casing is one to two times larger than a stator for the rotor of the outer volume of the emulsion dispersion machine, is preferably. The emulsion dispersion machine is batch with continuous processing that means each of the materials from metering pumps passing an emulsification chamber of the emulsion dispersion machine at one way passing but waiting at once when volume of the emulsion chamber casing is two to twenty times larger than a stator for the rotor of the outer volume of the emulsion dispersion machine, is preferably. The emulsion dispersion machine is near batch that means each of the materials from metering pumps waiting at once to reach predetermined amount in an emulsification chamber of the emulsion dispersion machine when volume of the emulsion chamber casing is twenty to two thousands times larger than a stator for the rotor of the outer volume of the emulsion dispersion machine, is preferably. The emulsion dispersion machine is batch and manufacturing a part of W/O type emulsification coagulant can be acceptable, but it is necessary to use metering pump. Because, if it doesn't use metering pump, decreasing emulsification efficiency and difficult to manufacture the tofu coagulant stably. And, the obtained tofu coagulant is kept into receptacle to refrigerate in the dark place, is preferably. The obtained tofu coagulant is into container and keeps refrigeration storage or chilled distribution, and within ten days from manufactured to use the tofu coagulant in soymilk coagulation machine at far place, is acceptable.

According to the present invention, the metering pump for the liquid food oil or the mineral salt solution is such as a self-suction quantitative pump is preferably. To be specific, a positive displacement pump, such as rotary pumps, tubing pumps (hose pumps), gear pumps, sign pomp (as tread mark), MONO pumps, screw pumps, vane pumps, and MONOFLEX pumps, is preferred. And low pulsation type pumps are more preferred. For batch type, the metering pump for the liquid food oil or the mineral salt solution, to be specific, diaphragm pumps, and plunger pumps, is preferred. And those pumps cascades and accumulator prepared, is preferred. The produced tofu coagulant pumping pathway from the emulsion dispersion machine by a metering pump in which the metering pump structure to be less shear force and friction heat occurs. The flow volume of the self-suction quantitative pump is controlled PID control by flow-meter, is preferred. PID control is arranged proportional control, integral control, and derivative control, and converging to a predetermined value. An automatically controlled so as to synchronize equipment in conjunction with the tofu coagulant producing apparatus post-processing. And, another metering pump for a soymilk pumping pathway that is the self-suction quantitative pump and automatically controlled, is preferred.

According to the inventor's knowledge, for manufacturing W/O type tofu coagulant without emulsifier, is used the one way passing preferably, and it is important to control rate the water phase versus the oil phase such as the mineral salt solution versus the liquid food oil, and it is important control flow volume for the mineral salt solution and the liquid food oil, and it is important to keep predetermined temperature for the mineral salt solution and the liquid food oil during stirred, and it is important pressure force at the stirring. Concerning the flow volume control, not only mixing but also strong stirring force of an emulsion dispersion machine is needed for keeping emulsification state long time. Concerning the materials temperature at emulsification and pressure force in the process that effect to the stability after emulsification. As above the tofu coagulant add into soymilk such as warmed soymilk, immediately, is important. The tofu coagulant keep refrigeration about one to two hours, and use it, is acceptable. The tofu coagulant stability is different as arrangement food fat oil and kinds of tofu products. This invention producing for Kinugoshi tofu (silken tofu), also available producing Momen tofu and Fried tofu sheet etc. The emulsion dispersion machine for stirring the liquid food oil with the mineral salt solution to an emulsification phase that is manufactured by Pacific Machinery & Engineering Co., Ltd., named Milder, example, is preferred. The machine rotor speed is between 5,000 to 10,000 rpm. The other type of emulsion dispersion machine preferably is, high-pressure homogenizer stator and diaphragm-type high-rotation type mixing, static mixers even better. The machine can be use a unit, and can be use the machines cascade connection which is structured multi-steps for mixing to finishing.

According to the present invention, the another dispersion machine for stirring the soymilk with the tofu coagulant that is manufactured by Primix Co., Ltd., named T.K. pipeline homomixer, or Izumi Food Machinery Co., Ltd., named Emalder, example, is preferred. The machine rotor speed is between 1,000 to 5,000 rpm. And, static mixer such a made by Noritake, and static mixer TS manufactured by Takai Tofu & Soymilk Equipment Co., is used to the machine. The machine can be use a unit, and can be use the machines cascade connection. The dispersion condition of the invention is same or small power against the prior art machine uses the commercially available emulsifier. Therefore, the present invention machine can be use in expensive dispersion machine and maintenance cost is saving.

According to the present invention, for example, W/O type emulsion is formed that stirred a water phase of mineral salt solution and a oil phase of liquid food oil including diacylglycerol (DAG) 1 wt % or more, the water phase versus the oil phase is 1:0.2 to 1:3 weight, is preferred. And the water phase versus the oil phase is 1:0.4 to 1:1.5 weight, is more preferred. Those ranges are inexpensive, and the oil phase less than the range is unstable, and the oil phase over than the range is too much expensive. The food oil for emulsification is necessary to liquid. The tofu coagulant can be keep into refrigerator, but it can not pumping when the oil is crystallized. Thus, as above explanation, warm the tofu coagulant up to liquid for using. Near melting point and flowing or even soften is acceptable to pump by metering pump. It can be using Palm oil or Coconut oil such high-melting point oil. It can be using high-melting point oil blended. But, in case of use the high melting point of the oil, the content of the oil is 50% or less. For example, heating means are arranged on tanks, pathways, and/or production-ways, is effective to smooth flowing.

According to the present invention, for example, inner diameter of a liquid food oil pumping pathway is between 1 and 15 mm, and inner diameter of a mineral salt solution pumping pathway is between 1 and 15 mm. So, those narrow pathways are connected and add the mineral salt solution pumping to the liquid food oil pumping, and then both materials are blended put momentum, and stirred finely by a strong emulsion dispersion machine. Therefore, the tofu coagulant W/O type emulsion is obtained which does not added any commercially available emulsifier, and this way can be keep the emulsification state long time against current method. Each flow the pathway enough to form turbulent range 0.1 to 1,000 m/sec, preferably range 1 to 100 m/sec. The static mixer is provided with an auxiliary front step of the dispersion machine, is more effective. The static mixer can be premixed at low flow rate. And the tofu coagulant W/O type emulsion adds into soymilk such warmed soymilk. The soymilk is used without any commercially available emulsifier such a defoamer. Therefore, finally tofu products are obtained only natural organic materials.

According to the present invention, a pathway joined the liquid food oil pumping pathway and the mineral salt solution pumping pathway, is shorten connected to the emulsion dispersion machine, is preferred. And pre-mixer such a static mixer is arranged into the pathways, are preferred. And the liquid food oil pumping pathway is connected directly to an emulsification chamber of the emulsion dispersion machine, and the mineral salt solution pumping pathway is connected directly to the emulsification chamber, is preferred. Concerning stirring the liquid food oil with the mineral salt solution, not only the way the mineral salt solution into the liquid food oil, but also upper position of a flowing is the mineral salt solution such a specific gravity range 1 to 1.4, and lower position of the flowing is the liquid food oil such a specific gravity range 0.8 to 0.9, is preferred. That means, avoid a structure both liquid separately and consider piping shape and connection style for both liquid mixtures, easily.

According to the present invention, the mineral salt solution pumping pathways are cascaded, and the mineral salt solution is added multiple and the mineral salt solution is added predetermined ratio for producing the tofu coagulant, wherein the water phase and the oil phase are stirred and mixed to W/O type emulsion, is preferred. And, the emulsion dispersion machine is preferably provided for each machine connected to the route shortly after the liquid food oil pumping pathway connected with the mineral salt solution pumping pathway. The emulsion dispersion machines can be applied static type and driven type. Those emulsion dispersion machines can be using same specification. The emulsion dispersion machines are arranged in steps of dispersion force to be fine emulsion from a coarse emulsion, is preferred.

According to the present invention, incrementally added the mineral salt solution to the liquid food oil, so that increasing efficiency of emulsification. Even, current fats difficult to emulsify can also applies this invention, can blend coagulant different from, can reduce the oil phase, and emulsified state can be maintained longer.

According to the present invention, further comprising a cooling unit is arranged to the liquid food oil pumping pathway and/or the mineral salt solution pumping pathway. For keeping the tofu coagulant emulsification state and obtains slow-acting, the cooling unit is preferably provided to the route shortly after the emulsion dispersion machine, and/or the cooling unit is preferably provided to around the emulsion dispersion machine. The cooling unit is double pipe heat exchangers or corrugated tube, for example.

As described below, the trend in the tofu coagulant comprising the concentrated mineral salt solution with rather less oil phase, is easily to heat up, but emulsification viscosity is getting higher by cooling, so can be control emulsification condition stably. As usual, chiller or antifreeze range −40 to −10 deg C. pass each of the codling units arranged on pathways, and indirectly cooled. Each material into refrigerator just before use, or the apparatus into cold storage room, is even better. The obtained tofu coagulant preferable temperature is 50 deg C. or less, 30 deg C. or less is better, 20 deg C. is much better.

According to the present invention, further comprising a cooling unit is arranged to the emulsion dispersion machine and/or a pressing unit is arranged to the emulsion dispersion machine.

The concentrated mineral salt solution emulsification dispersion with food oil, is easily to heat up such a thermal agitation, so that the cooling unit is arranged to the emulsion dispersion machine is preferred. If do a emulsification dispersion without cooling continuously, more heat up and dispersed particles to coalesce, then emulsification condition unstable and slow-act deteriorate, sometimes. In case of target cooling temperature is room temperature or more, air cooling is acceptable. In case of target cooling temperature is room temperature or less, water cooling indirect or refrigerant such a chiller indirect is better. Either, it is necessary that at least partial or heat absorbing most of the above stirring. The cooling temperature lower limit is a melting point of the food oil. To be specific, the cooling temperature lower limit is a lower melting point of the food oil depends on crystalline form. And, to be specific, the cooling temperature lower limit should be not less than the freezing point of the concentrated mineral salt solution. As usual, chiller or antifreeze range −40 to −10 deg C. pass each of the cooling units arranged on pathways, and indirectly cooled. Each material into refrigerator just before use, or the apparatus into cold storage room, is even better.

And the pressing unit is arranged to the emulsion dispersion machine, so that under pressure to suppress cavitations during emulsification dispersion, emulsification efficiency loss can be prevented. Normally, valve, orifice, back pressure valve, and control valve is used to minimize, and inner pressure level is adjusted range 0.001 to 1.0 M Pa, and preferably adjusted range 0.01 to 0.3 M Pa. Normally, W/O type tofu coagulant viscosity is 2,000 cP or more. The tofu coagulant viscosity is range 10 to 100 times higher than the liquid food oil and the mineral salt solution. The trend in the pathways, inner pressure level at after the emulsifying dispersion machine is higher than at before the emulsifying dispersion machine, so that back pressure valves are arranged to the feedback pathways, is preferred.

According to the present invention, further comprising a flow-meter with indicating controller for control discharge rate of the metering pump is arranged to the liquid food oil pumping pathway and/or another flow-meter with indicating controller for control discharge rate of the another metering pump is arranged to the mineral salt solution pumping pathway, is preferred.

According to the present invention, particularly feedback control, adjusting the flow rate fluctuations few at valve switching, and after valve switching can be a stable flow immediately. From a state where the flow is stable, the switching valve, the pumping rate in a stable condition even if production is supplied to the state from standby. Also, mixture by pumping even emulsifying dispersion machine, mixed in set ratio, so easily obtained early emulsification conditions, also prevent slight irregularity.

According to the present invention, further comprising a feedback pathway is arranged to the liquid food oil pumping pathway and/or a feedback pathway is arranged to the mineral salt solution pumping pathway, and wherein a back-pressure means is arranged on each of the feedback pathway.

According to the present invention, particularly material feedback pathways are arranged, and back pressure means as back pressure valves are arranged, those back pressure valves adjusting the flow rate fluctuations few at valve switching, and after valve switching can be a stable flow immediately. From a state where the flow is stable, the switching valve, the pumping rate in a stable condition even if production is supplied to the state from standby. Also, mixture by pumping even emulsifying dispersion machine, mixed in sec ratio, so easily obtained early emulsification conditions, also prevent slight irregularity. As above, an inner pressure occurs aver the emulsifying dispersion machine; even the back pressure valves press higher pressure, so that process before the emulsifying dispersion machine press the pressing force to the emulsifying dispersion machine for keeping pressure balance is necessary. Then, each pathway is formed as that pressure condition by metering pumps. To reduce the affects of fluctuations due to long-term use and delicate pulsation of pumps to stabilize the pressurized state, the circulation pathway feeding of each raw material (return line) tends to increase the pressure from the back pressure unit. On the other hand, to control a constant pressure, it has the effect of stabilizing a constant state of the emulsifying dispersion machine emulsion. According to the invention, arrange the back pressure means at the outlet piping from the right or after the emulsifying dispersion machine, is preferred. In addition, also preferred to arrange the back pressure means at pipe that provide materials to the emulsifying dispersion machine.

According to the present invention, a machine for soymilk coagulation, comprising the tofu coagulant producing apparatus according to any one of above inventions, and further comprising: a produced tofu coagulant pumping pathway from the emulsion dispersion machine; a soymilk pumping pathway from a soymilk tank by a metering pump; wherein the produced tofu coagulant pumping pathway is connected with the soymilk pumping pathway, and both the pathways are connected to a dispersion machine for stirring the soymilk with the tofu coagulant.

According to the present invention, a machine for soymilk coagulation, comprising the tofu coagulant producing apparatus according to any one of above inventions, and further comprising: a produced tofu coagulant pumping pathway from a tofu coagulant tank by a metering pump; a soymilk pumping pathway from a soymilk tank by another metering pump; wherein the produced tofu coagulant pumping pathway is connected with the soymilk pumping pathway, and both the pathways are connected to a dispersion machine for stirring the soymilk with the tofu coagulant.

As the present invention, a machine for soymilk coagulation is, the tofu coagulant emulsion produced by the tofu coagulant producing apparatus, wherein the tofu coagulant predetermined amount is added to a soymilk, demulsification by a dispersion machine for stirring the soymilk with the tofu coagulant. The dispersion machine stirs the soymilk with the tofu coagulant continuously and demulsificate the tofu coagulant in the machine, and coagulate to the soymilk.

According to the present invention, a machine for soymilk coagulation, the tofu coagulant comprising a mineral salt solution as water phase and a food fat as oil phase, a diacylglycerol (DAG) is 1 wt % or more included. In particularly, the concentration of mineral salt solution is 2M or more. Obtained the tofu coagulant comprising a mineral salt solution as water phase and a food fat as oil phase including a diacylglycerol (DAG) is 1 wt % or more, and wherein the water phase and the oil phase are stirred and mixed to W/O type emulsion. According to the tofu coagulant, wherein the concentration of mineral salt solution is 2 M or more, is preferably. Because, the concentration of mineral salt solution is up near to saturated aqueous solution, then effective tofu coagulation reaction to delay. That is, when emulsifying, emulsification coagulant viscosity increasing, and prevent dispersed particles (water phase) to coalesce, then emulsification condition stable, and the particles finer to more effective slow-acting. On the other hand, when target cooling temperature is below room temperature, indirect cooling means such as water chillers and water cooled refrigerant is better. The concentrated mineral salt solution emulsification dispersion with food oil, is easily to heat up such a thermal agitation, so that the cooling unit is arranged to the emulsion dispersion machine is preferred. And also, the pressing means for suppressing capitation cause of stirring heat, is arranged to the emulsion dispersion machine is more preferred.

W/O type emulsion is obtained DAG, is shown in related art 2, 3. The processing oil comprises DAG about 87%. Generally, fat comprising DAG high concentration that characteristics is high melting point range 20 to 70 deg C., except linoleic acid and Linolenic acid, is shown in related art 9. This oil is solidified at room temperature, but there is no comment in the above related art. If uses a coagulant comprising mineral salt solution as shown in Patent document 4, is dispersed into solidified oil, difficult automatic control to coagulate soymilk. Actually, in case of uses commercially available coagulant emulsion, it is quite difficult to wash pathways and tanks by water. Because, the commercially available coagulant emulsion become high viscosity product mixtures with water. The product is difficult to remove from wall surface by water in a little detergent. According to the present invention, the tofu coagulant is used liquid state at melting point or more before using by heating means. The tofu coagulant is used liquid state before adding soymilk. For example, heating means are arranged on tanks, and valves, is effective to smooth flowing.

For example, Rice oil, Rice-bran oil, and Cottonseed oil such as natural oil including DAG range 5 to 10%, is fatty acid composition of the high melting point DAG, is estimated. This invention uses the small quantity of the tofu coagulant, thus machine handling is not affective. The present invention of tofu coagulant has more hydrophilicity than soybean oil comprises DAG between 1 and 2%, i.e. the tofu coagulant is low interfacial tension. According to the present invention of tofu coagulant, comprises a concentrated magnesium chloride solution as a dispersed phase and a liquid fat as a continuous phase, thus, the water phase and the oil phase are stirred and mixed to W/O type emulsion and stable W/O type emulsion is formed, we found it. The above things, other than any of constituents, first revealed that DAG effect quality. As the prevent invention, the tofu coagulant that stuck on wall surface, pathways, and tanks will demulsificate at once, and easy to wash by water in a little detergent. The tofu coagulant is handling easy, and is not affective environment.

The present invention of tofu coagulant, wherein the food fat comprises DAG 1% or more. DAG shows a form of two molecules of fatty acid and ester-linked glycerol molecule. Any emulsifier is not comprised in the invention tofu coagulant. The present invention of tofu coagulant, the food fat is added food additives as processing aid in the general fat manufacturing process that is no problem, and the food fat is added chemical processing such a transesterification and curing process of hydrogenation that is no problem. The food fat is obtained in the general oil expeller process that is not processed any special processing, preferably. That is to say, the food fat comprises Monoacylglycerol (MAG) 1% or less and the food fat is not contains lecithin (phospholipid) such as emulsification, preferably. The food fat comprises DAG is 1% or more and DAG is less than 10%, that is economical condition and suitable for this invention. The food fat such a processing oil comprises DAG is 10% or more, is more suitable for this invention, but, it is not easy to handle because it is solidified at room temperature and material cost is increased, thus the composition of the food fat is chosen by the cost-effectiveness.

The present invention of tofu coagulant, the food fat is not limited. For example, Rice oil, rice-bran oil, rice-germ oil, Corn oil, Soybean oil, Rapeseed oil, Canola-seed oil, Sunflower oil, Safflower oil, High-oleic-safflower oil, Sesame oil, Palm oil, Palm-kernel oil, Olive oil, Virgin-olive oil, Pure-olive oil), Grape-seed oil, Hazelnut oil, Palm oil (Coconut oil), Cottonseed oil, Peanut oil, Macadamia-nut oil, Almond oil, Avocado oil, Linseed oil, Pumpkinseed oil, Walnut oil, Sesame oil, Cashewnut oil, Wheat-germ oil, Borasseed oil, Evening-primrose oil, Borage oil, Black-currantseed oil, Camellia oil, Rose-hip-seed oil, Apricot-kernel oil, Niger-seed oil, Tea-seed oil, Hemp-seed oil, Black-mustard-seed oil, Shea-butter oil, Cacao butter and other vegetable oils, Fish oil, Animal fat (Tallow, Lard, Chicken Fat, Whale oil, Seal oil) is used as the food fat, and also those blend oil is acceptable. It is easy to blend flavors, such as oil, sesame oil and seasoning oil into the food fat. Those ingredients of the food fat (fruits and seeds, including the germ meal and after milling), oil mill (such as cold-pressed method), purified (de-gumming and de-acidification wintering) conditions such as oil, Hydrogenated esters and other processing conditions such as replacement blends conditions, DAG content and emulsion stability are different.

Many commercially available natural oils comprise DAG 1 to 20% (often 1 to 10%, reference related art document 8). The present invention of tofu coagulant, the food fat comprises DAG is 2% or more, is preferably. And the food fat comprises DAG is 5% or more, is more preferably. It is acceptable blended natural fat and processing fat, for example, the natural fat and processing fat ratio is between 1:0.01 and 1:100. There are limitations to blends cost-effective. Thus, the natural fat and processing fat ratio is between 1:0.02 and 1:1, is preferably. In case of blend uses blend method for the natural fat comprises a few DAG, thus, DAG 1% or more is obtained, and DAG 2% or more is obtained, further more DAG 5% or more is obtained. As shown in reference related art document 9, DAG in the fat of natural origin for the 1, 2-DAG and 1, 3-DAG ratio is 3:7. The invention is a tofu coagulant for tofu made from soybeans. Therefore, the emulsified tofu coagulant is vegetable oil is preferably. When uses the food fat, check DAG content and check oil quality, oil mill conditions, processing conditions and purification conditions, and also by other manufacturers and product upgrades. Because, those conditions are different to be DAG content is different.

Generally, most commercial food fats consist TAG mainly, and DAG is a few percent, is described in related art document 4 and 8. Innovators analyzed the commercial food fats at Japan institute of oil & fats, other foods inspection foundation. And the result is, rice oil comprises DAG 9.9%, cottonseed oil comprises DAG. 7.8%, see Table 4. Cottonseed oil different of origin, and DAG is between 5.4 and 9.5%, is described in document 6. The present invention of a tofu coagulant comprising a mineral salt solution as water phase and a food fat as oil phase, without emulsifier including a diacylglycerol (DAG) is 1 wt % or more. The commercial food fat products comprise DAG between 1 and 10%, and processing fat comprises DAG between 40 and 99%. In particularly, the concentration of mineral salt solution is 2M or more. The invention is an apparatus for producing as above the tofu coagulant, and the invention is a machine for soymilk coagulation that comprise the tofu coagulant apparatus and the tofu coagulant producing apparatus connected a soymilk pathway, wherein the soymilk mixture with the obtained tofu coagulant, and dispersion by the dispersion machine, and producing a tofu such a pudding. These systems (apparatus, machine) are quite new and no other prior art.

DAG is a food fat component that is comprised a number of commercial oils. The food fat comprises Monoacylglycerol (MAG), and MAG is useful as an emulsifier. DAG is a fat which is same as conventional triacylglycerol (TAG). DAG, MAG and TAG are belongs to Glycerin fatty acid Glycerol esters of fatty acids. Emulsification of DAG is weaker than MAG. DAG is a fat which has a weak emulsification, is described in document 2. However, there is no commercial emulsifier which comprises DAG mainly. Fat product comprises DAG 40% or more, is produced by enzymatic reaction from glycerol and fatty acids, so treated as processing fat and not treated as emulsifier. Study to W/O type emulsion characteristic that is used 0.5M magnesium chloride solution and processing oil and does not use additives as emulsifiers, is disclosed in related art document 3. The processing oil comprises DAG about 87%.

The present invention refers DAG, is not into processing oil and it is into the food fat naturally. DAG is formed that one glycerol molecule, a form of carbon consisting of approximately C8 to C24 fatty acid molecule consisting of two. Most commercial oils contain that DAG, the difference in the difficulty of the content, but either can be used to the invention.

When using commercial fat or commercially processed fats comprises relatively strong emulsification with lecithin and MAG coexistence with DAG, may have adverse effect on emulsion stability and slow-acting soymilk coagulation. Thus, phospholipid as lecithin is between 0 and 0.1% and MAG is between 0 and 1% that is preferably. High acid value is better within the Japanese Agricultural Standards. Free fatty acid content is calculated from the average molecular weight as well, as acid value, and High free fatty acid content is better. The present invention of a tofu coagulant, wherein the free fatty acid content is 0.05% or more and acid value is 0.1% or more, is preferably. The free fatty acid has a weak emulsification. Those phospholipid, MAG and free fatty acid are almost rejected de-gumming and de-acidification wintering at purified process. TAG is a main content of fat in generally, is not important to this invention. Thus, TAG is between 0 and 98%. Others may be included in the trace, tocopherols (vitamin E), polyphenols and sterols are not affected by this invention thus, that content is not limited. Sometimes, the tempura frying oil products comprises small amount silicone defoamer. The silicone deformer affects to the surface tension of the oil, but the silicone deformer is almost no affective to the surface tension and emulsification of the oil for the present invention. For processed food products such as organic produce is not available sometimes, thus, preferable to select a product no containing silicone.

The present invention, maximum amount of DAG is no upper limit, but, normally DAG is between 1% to 10%. According to the invention, DAG less than 1% is not useful. And processing oil that comprises DAG 40% to 90% is available to single use or blend use for this invention. Generally, melting point of DAG is higher than TAG, thus, large amount of DAG is easy to solidify and affect stabilization of emulsification. Related art 9 shows, DAG melting point is that 1,3-DAG-Jirinoren is −2.6 deg C., 1,3-Jirinorein is −12.3 deg C., and Jiorein is 21.5 deg C. Generally, 1,2-DAG is range 20 to 70 deg C. so that is high melting temperature.

In case of uses low melting point of DAG mainly, large amount of DAG is not to solidify and not affect stabilization of emulsification. In case of uses high melting point of DAG, warm and emulsified dispersion is preferably. Particularly, uses a fat that comprises high melting point of DAG, keeping a warm temperature higher than DAG melting point during emulsification that is easy to form W/O type emulsification. Because, it is no trouble happens that weighting and other operations, automatically. And after emulsification, can be kept W/O type emulsification into refrigerator for some days stable. For example, the emulsified tofu coagulant is warmed upper than melting point of DAG, and the fat is kept the liquid, before addition to soymilk, is preferably in the handling of the machine.

EFFECTS OF THE INVENTION

According to the invention soymilk coagulation machine for tofu products, controls such as cooling and emulsifying, and the water phase Nigari and the oil phase fat are stirred and mixed to W/O type emulsion, easily, without emulsifier. And obtained tofu coagulant is given effective late-acting, and mixture with soymilk can be produce truly natural food. And easy to follow processed foods organic produce such Japan agriculture standard. And produce Kinugoshi tofu used as above the tofu coagulant, obtains smooth skin, high water retention, with the original flavor of tofu, honed to a silken tofu-like elasticity and hardness of water-holding firm., the tofu coagulant characterised slow-acting coagulating reaction is obtained by low cost. As the prevent invention, the tofu coagulant that stuck on wall surface, pathways, and tanks will demulsificate at once, and easy to wash by water in a little detergent. The tofu coagulant is handling easy, and is not affective environment. The scope of the invention, as well as silken tofu, kinugoshi-tofu, momen-tofu, namaage-tofu, atuage-tofu, can utilize a variety of tofu products.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view illustrating of the first embodiment as the soymilk coagulation machine with one-way continuous pathway comprising the tofu coagulant producing apparatus according to the present invention.

FIG. 2 is a schematic view illustrating another example as the tofu coagulant producing apparatus according to the first embodiment.

FIG. 3 is a schematic view illustrating another example as the tofu coagulant producing apparatus according to the first embodiment.

FIG. 4 is a schematic view illustrating of the second embodiment as the soymilk coagulation machine with batch circulation comprising the tofu coagulant producing apparatus according to the present invention.

FIG. 5 is a schematic view illustrating another example as the tofu coagulant producing apparatus according to the second embodiment.

FIG. 6 is a schematic view illustrating of the third embodiment as the soymilk coagulation machine with one-way continuous pathway comprising the tofu coagulant producing apparatus according to the present invention.

FIG. 7 is a schematic view illustrating of related art as the soymilk coagulation machine.

DETAILED DESCRIPTION OF THE INVENTION

Next, the description will be made concerning concrete embodiments according to the present invention by referring to the drawings.

First Embodiment

According to the invention, FIG. 1 shows first embodiment as the soymilk coagulation machine Z1 with one-way continuous pathway comprising the tofu coagulant producing apparatus N1 according to the present invention. The tofu coagulant producing apparatus, comprising: a liquid food oil pumping pathway H1 from a liquid food oil tank T1 by a metering pump P1; a mineral salt solution pumping pathway H2 from a mineral salt solution tank T2 by another metering pump P2; an emulsion dispersion machine M1 for stirring the liquid food oil with the mineral salt solution to an emulsification phase; wherein the liquid food oil pumping pathway H1 is connected with the mineral salt solution pumping pathway H2 at junction B1, and the mineral salt solution is added predetermined ratio for producing the tofu coagulant, wherein the water phase and the oil phase are stirred and mixed to W/O type (water in oil type) emulsion (without emulsifier), and a back pressure valve V3 is arranged on output the emulsion dispersion machine M1. The soymilk coagulation machine Z1, comprising the tofu coagulant producing apparatus N1, and further comprising: a produced tofu coagulant pumping pathway H4 from the emulsion dispersion machine M1; a soymilk pumping pathway H5 from a soymilk tank T3 by a metering pump P3; wherein the produced tofu coagulant pumping pathway H4 is connected with the soymilk pumping pathway H5 at junction B2, and both the pathways H4, H5 are connected to a dispersion machine M2 for stirring the soymilk with the tofu coagulant. That is, the soymilk coagulation machine Z1 comprises coagulant preparation part and soymilk coagulation part. And, the liquid food oil pumping pathway H1 is connected directly to an emulsification chamber of the emulsion dispersion machine M1, and the mineral salt solution pumping pathway H2 is connected directly to the emulsification chamber, is acceptable.

As shown in FIG. 1, according to the embodiment, comprising a cooling unit R1 is arranged to the liquid food oil pumping pathway H1, and a cooling unit R2 is arranged to the mineral salt solution pumping pathway H2. The cooling unit R1 or R2 can be omitting. As shown in FIG. 1, according to the embodiment, comprising a feedback pathway K1 is arranged to the liquid food oil pumping pathway H1 and wherein a back-pressure means V1 is arranged on the feedback pathway K1. And, feedback pathway K2 is arranged to the mineral salt solution pumping pathway H2 and wherein a back-pressure means V2 is arranged on each of the feedback pathway K2.

Those back pressure means V1, V2 are used to minimize, is preferable. The back pressure means V1, V2 is using positive displacement pumps, ball cock, butterfly valves, control valves, siphons, orifice, back pressure valve (manual, including auto or manual), flow control valve (flow control valves), etc., either using the even better, some combination of these units. Those back pressure means V1, V2 adjusting the flow rate fluctuations few at valve switching, and after valve switching can be a stable flow immediately. From a state where the flow is stable, the switching valve, the pumping rate in a stable condition even if production is supplied to the state from standby. Also, mixture by pumping even emulsifying dispersion machine, mixed in set ratio, so easily obtained early emulsification conditions, also prevent slight irregularity.

Symbol R code means a cooling unit in the position indicated (heat exchanger) in FIG. 1 is preferably provided. The embodiment apparatus Z1, the produced tofu coagulant pumping pathway H4 follows the tofu coagulant producing apparatus N1, is not arranged with a number of components that could damage the emulsion, such as pumps, valves, and hopper. A junction B2 is not use a valve, and a pipe H5 connected with a pipe H4. The produced tofu coagulant is not receiving physical stimuli, and heating except cooling, is preferred.

A cooling unit R1 is arranged to the liquid food oil pumping pathway H1, and a cooling unit R2 is arranged to the mineral salt solution pumping pathway H2. A plate heat exchanger, a double-tube heat exchanger such as indirect heat exchanger tubes is uses for the cooling unit R1, R2. A double-jacket, double-tubes, and a bellows tube such as indirect heat exchanger tubes is uses for the storage tanks T1, T2, is preferred.

Heat exchanger R is preferable arranged at junction B1, the pathway H1 connecting with the pathway H2 (See symbol R in FIGS. 1 to 5). To keep an emulsification condition due to soymilk coagulation process, the obtained tofu coagulant preferable temperature is 30 deg C. or less, 20 deg C. is better, so that pumping the obtained tofu coagulant used by heat exchanger piping. According the embodiment, keep the obtained tofu coagulant range −10 to 30 deg C. (preferable range 0 to 20 deg C.) due to soymilk coagulation process uses by cooling unit (heat exchanger) R1, R2, R, etc. Has the effect of lower temperature to stabilize the emulsified state, and cooled to near the melting point of fats, increases the oil viscosity, easy to maintain a stable emulsified finely dispersed state, slow-acting increase the soymilk coagulation. When temperature below the melting point (below the freezing point), blockage in the pipe, so that handling difficult.

The emulsion dispersion machine M1 for stirring the liquid food oil with the mineral salt solution to an emulsification phase, is preferred. The machine rotor speed is between 2,000 to 30,000 rpm, preferable between 5,000 to 20,000 rpm, and a rotor peripheral speed is between 1 to 20 m/sec., preferably 5 to 15 m/sec. The minimum clearance between rotor and stator is preferably 0.1 to 2 mm. Embodiment emulsifier dispersion machine M1 is made from within the rotor and stator, the gap between the rotor and stator and rotor rotation, shear force is generated, to achieve emulsification. And a pressing unit is arranged to the emulsion dispersion machine M1, so that under pressure to suppress cavitations during emulsification dispersion, emulsification efficiency loss can be prevented. Normally, valve, orifice, back pressure valve, and control valve is used.

According to the embodiment, a dispersion machine M2 for stirring the soymilk with the tofu coagulant that is arranged at the soymilk pumping pathway H5. A static mixer such a made by Noritake, and static mixer TS manufactured by Takai Tofu & Soymilk Equipment Co., is used to the dispersion machine M2.

A cooling unit (heat exchanger) R is built-in the emulsion dispersion machine M1 Then, chiller or antifreeze (preferable under 10 deg C., between 0 to 5 deg C. chiller, −40 to 5 deg C. antifreeze) through the emulsion dispersion machine M1, so that the mineral salt solution and the liquid food oil are controlled there temperature prescribed temperature (under 70 deg C., preferable under 30 deg C., better under 20 deg C.). And a pressing unit is arranged to the emulsion dispersion machine M1. The cooling unit is arranged to the emulsion dispersion machine M1 and/or a pressing unit is arranged to the emulsion dispersion machine M1. Under limit temperature of the mineral salt solution and the liquid food oil are acceptable the freezing point of liquid coagulant or more above the melting point and freezing point of the fat, well below 0 deg C., typically in the range of −10 deg C. to 0 deg C.

FIG. 2 shows a schematic view illustrating another example as the tofu coagulant producing apparatus N2 according to the first embodiment. The emulsion dispersion machines M1 a and M1 b are cascaded. That is, the emulsion dispersion machines M1 a and M1 b are arranged in steps of dispersion force to be fine emulsion (main-emulsification) from a coarse emulsion (pre-emulsification), is preferred. The advantages of this case, the emulsified state can be maintained longer, an emulsifying dispersion machine M1 a, M1 b does not have to use the powerful stuff, and mentioned the advantage of more uniform particle size emulsion. The liquid food oil pumping pathway H1 consist as a circular path, the mineral salt solution pumping pathway H2 consist as a circular path, the back-pressure means V1 is arranged on the feedback pathway K1. And, feedback pathway K2 is arranged to the mineral salt solution pumping pathway H2 and wherein a back-pressure means V2 is arranged on the feedback pathway K2. The emulsion dispersion machines M1 a and M1 b are used stator and rotor type of high-rotation mixing, static mixers even better as the machines M1, and M1 a and M1 b are arranged in steps of dispersion force to be fine emulsion (main-emulsification) from a coarse emulsion (pre-emulsification), is preferred.

According to the embodiment, further comprising a flow-meter F1 with indicating controller for control discharge rate of the metering pump P1 is arranged to the liquid food oil pumping pathway H1 and a flow-meter F2 with indicating controller for control discharge rate of the metering pump P2 is arranged to the mineral salt solution pumping pathway H2. The flow volume of the self-suction quantitative pump is controlled PID control by flow-meter F1, F2, is preferred. PID control is arranged proportional control, integral control, and derivative control, and converging to a predetermined value. An automatically controlled so as to synchronize equipment in conjunction with the tofu coagulant producing apparatus N2 post-processing.

FIG. 3 shows a schematic view illustrating another example as the tofu coagulant producing apparatus N3 according to the first embodiment. The mineral salt solution pumping pathways are cascaded, and the mineral salt solution is added multiple and the mineral salt solution is added predetermined ratio for producing the tofu coagulant, wherein the water phase and the oil phase are stirred and mixed to W/O type emulsion, is preferred. A liquid food oil pumping pathway H1 from a liquid food oil tank T1 by a metering pump P1, and mineral salt solution pumping pathways H2 from a mineral salt solution tank T21, T22, T23 cascaded from other metering pumps P2, P3, P4.

Second Embodiment

According to the invention, FIG. 4 shows second embodiment as the soymilk coagulation machine Z2 with batch circulation comprising the tofu coagulant producing apparatus N4 according to the present invention. The tofu coagulant producing apparatus N4, comprising: a liquid food oil pumping pathway H1 from a liquid food oil tank T1 by a metering pump P1; a mineral salt solution pumping pathway 112 from a mineral salt solution tank 12 by another metering pump P2; an emulsion dispersion machine M1 for stirring the liquid food oil with the mineral salt solution to an emulsification phase; wherein the liquid food oil pumping pathway H1 is connected with the mineral salt solution pumping pathway The emulsion dispersion machine M1 (B1) comprises a batch container with stirring unit. In this case, batch that means each of the materials from metering pumps P1, P2 waiting at once to reach predetermined amount in an emulsification chamber B1 of the emulsion dispersion machine M1. One emulsion dispersion time is 10 seconds to 60 minutes. That is, once, twice to produce W/O type (type water in oil) tofu coagulant, and transfer into the hopper by scooping up such as ladle.

The soymilk coagulation machine Z2, comprising the tofu coagulant producing apparatus N4, and further comprising: a storage tank Tt for the obtained tofu coagulant keeps, a soymilk pumping pathway H5 from a soymilk tank T3 by a metering pump P3, a emulsion dispersion machine M1. The produced tofu coagulant is pumping by a metering pump Pt and into the dispersion machine M2. For soymilk coagulation part is not limit as FIG. 4, so that means, uniformly dispersed emulsion coagulant in soymilk is desirable that the mixer has a mixing effect on the emulsifying solution. For example, one-two formula coagulation machine, coagulation machine with screw, continuous or batch coagulation machine using a static mixer or rotary mixer stirred in in-line static mixer or rotary mixer stirred in the stirring force is strong in-line distributed), is preferably be used.

The emulsion dispersion machine M2 that volume of the emulsion chamber casing is twenty to two hundreds times larger than a stator for the rotor of the outer volume of the emulsion dispersion machine M2. The emulsion dispersion machine M2 outside a double jacket cooling unit to enhance the cooling effect can also be provided with a corrugated tube inside the cooling unit can to stabilize the tofu coagulant emulsion state. Although not shown, with several having to switch to a batch container equipped with an emulsion dispersion machine alternately, each batch from the container pumping by metering pump Pt continuously, is useful.

FIG. 5 shows a schematic view illustrating another example as the tofu coagulant producing apparatus N5 according to the second embodiment. A pipe H4 is connected under the tofu coagulant producing apparatus N5 (batch vessel is relatively large emulsion chamber, volume of the emulsion chamber casing is two to twenty times larger than a stator for the rotor of the outer volume of the emulsion dispersion machine), and the pipe H4 piping to a soymilk pumping pathway H5 from a soymilk tank T3 as shown in FIG. 4. In this example, be produced in a batch soymilk coagulant, can be continuously mixed with soymilk. Metering pump is arranged by sending a pipe pumping routes and soymilk coagulant, and the mixture uniformly coagulant and soymilk, and good quality soymilk coagulation. Here, although not illustrated, as reference in FIG. 1, soymilk pathway H4 is connected with the tofu coagulant producing apparatus N5, or soymilk pathway H4 is connected with metering pump, is preferred. The volume of the batch chamber (emulsion chamber) casing is one to ten times larger than an emulsion chamber casing of the emulsion dispersion machine M1. The residence time constant in the emulsion chamber (1 to 60 seconds) by providing a uniform and fine produce emulsified state. A double jacket cooling unit is arranged outside of the emulsion dispersion machine M1, and a corrugated tube cooling is arranged inside of the emulsion dispersion machine M1, be to stabilize the emulsion coagulant.

Third Embodiment

According to the invention, FIG. 6 shows third embodiment as the soymilk coagulation machine Z3 with one-way continuous pathway comprising the tofu coagulant producing apparatus N6 according to the present invention. As shown in FIG. 6, according to the soymilk coagulation machine Z3 is not having a cooling unit, flow-meter, and a feedback pathway. That is, the tofu coagulant producing apparatus N6, comprising: a liquid food oil pumping pathway H1 from a liquid food oil tank T1 by a metering pump P1; a mineral salt solution pumping pathway H2 from a mineral salt solution tank T2 by another metering pump P2; an emulsion dispersion machine M1 for stirring the liquid food oil with the mineral salt solution to an emulsification phase; wherein the liquid food oil pumping pathway H1 is connected with the mineral salt solution pumping pathway H2 at junction B1, and the mineral salt solution is added predetermined ratio for producing the tofu coagulant, wherein the water phase and the oil phase are stirred and mixed to W/O type (water in oil type) emulsion (without emulsifier). The soymilk coagulation machine Z3, comprising the tofu coagulant producing apparatus N3, and further comprising: a produced tofu coagulant pumping pathway H4 from the emulsion dispersion machine M1; a soymilk pumping pathway H5 from a soymilk tank T3 by a metering pump P3; wherein the produced tofu coagulant pumping pathway H4 is connected with the soymilk pumping pathway H5 at junction B2, and both the pathways H4, H5 are connected to a dispersion machine M2 for stirring the soymilk with the tofu coagulant.

Comparative Example

FIG. 7 is a comparative example related art as the soymilk coagulation machine. From emulsion dispersion machine M1 output connected to junction KB to feed back an emulsified product to a storage tank T4 by feedback pathway H3. As described in Patent document 1, in the comparative example shown in FIG. 7, in the process of circulating coagulant emulsion was emulsified produced in the course of the circulation, or to revert to its original state gradually emulsified phenomenon was to destroy the emulsion coagulant (emulsified solution) were found. Since metering pump is not arranged before the storage tank T4, and both a liquid food oil and a mineral salt solution doesn't pumping, so that primarily W/O type (water in oil type) is difficult to get emulsification coagulant. In other words, the density of liquid food oil is range 0.8 to 0.9, the density of coagulant is about 1.2 to 1.4, the water phase-oil phase ratio (by weight) needs even more than regulating the flow rate.

Producing Condition for Tofu Coagulant

According to the invention, the tofu coagulant comprises a mineral salt solution as water phase and a food fat as oil phase. The tofu coagulant is not included synthetic emulsifiers and stabilizers that both food additives are necessary to uses current emulsification. According to the tofu coagulant, wherein the mineral salt solution comprising at least any one of a magnesium chloride, calcium chloride, sodium chloride, potassium chloride, magnesium sulfate, magnesium chloride seawater crude, in particular the magnesium chloride as Nigari. The invention, Nigari is acceptable including less than the solubility of calcium sulfate, calcium sulfate and particulate matter, and organic acids such as citric acid and gluconic acid.

The present invention of tofu coagulant has food fat that comprises DAG between 1% or more. The invention uses the food fat as liquid condition that can be use translucent or milky-white either. Just, it is necessary to use liquid food fat. That is to say, at least before the emulsifying dispersion, keep the food fat temperature higher than it maximum melting point. The DAG is natural ingredient of the food fat. The present invention of tofu coagulant can use the commercial food fat. For example, Rice oil, Corn oil, Soybean oil, Rapeseed oil etc, comprises DAG between 0.1 and 15%, see table 4.

DAG content is depended on oil material, oil expression and purification. For example, virgin olive oil and pure olive oil comprises DAG, but content of DAG are deference. The invention, mixture virgin olive oil and pure olive oil, is no problem and it can be control emulsification stability and slow-acting characteristic by deferent DAG contents mixture. Professional cooking oil as silicone (antifoam) was added the product is few slow-acting effect on emulsion stability and soymilk coagulation. But, Lecithin and MAG are cause of weak slow-acting. Salad oil is acceptable that rejected depositions by wintering, but DAG with high melting temperature content very few is not useful for the invention, sometimes.

Table 4 shows emulsion easiness that how easy to W/O emulsion after emulsifying dispersion, emulsion stability that how keep W/O emulsion warms 45 deg C. Emulsion stability test procedure is, put the emulsion on glass plate and put cover glass on it and immediately view and photo by digital microscope (manufactured by Keyence Corporation named VHX-500F), after that input it chamber 45 deg C. and 1 hour, after that put out it and view and photo again, and compare both emulsions different. Measure particle diameters in photos and calculate particle size distribution.

Emulsifying dispersion temperature is depends on melting point of fat. In case of the fat temperature is 45 deg C., most of food fat is liquid. Emulsifying dispersion condition is adjustable such 35 deg C. and 2 hours or more, 25 deg C. and 4 hours or more, 15 deg C. and 8 hours or more, 5 deg C. and 16 hours or more. The invention of tofu coagulant, water phase size average is between 0.1 and 20 micro meter, average between 1 and 10 micrometer is preferably, average between 1 and 5 micrometer is more preferably.

According to the present invention, when the fat is solidified, pre-warmed over the melting point and liquid fat is stirred and mixed. And when the fat is solidified by cooling after emulsified, pre-warmed over the melting point and liquid the emulsified tofu coagulant is used before addition to soymilk. When use a fat easy to solidify, attaches a keeping heat means on pipes, tanks, and valves, preferably.

Example 1

Magnesium chloride solution as Nigari that is made by AKO KASEI CO., LTD., that named Soft-Wafer. Food fat is pure olive oil made by J-OIL MILLS, Inc. Temperature of the magnesium chloride solution is 19.1 deg C., and temperature of the olive oil is 10.3 deg C. or 4.1 deg C. The food fat is not including silicone. Magnesium chloride and water ratio is 2:1, and make a magnesium chloride solution that concentration is 66.7% w/w as density 1.3 and 4.3 M. Pre-mixture the magnesium chloride solution 500 g and olive oil 500 g separately, and sending each material to an emulsifying dispersion machine M1 and make a emulsified tofu coagulant. Emulsifying dispersion machine M1 is manufactured by Pacific Machinery & Engineering Co., Ltd., named Milder for laboratory. While set inner pressure range 0.001 to 1.0 MPa (preferable 0.01 to 0.3 MPa) to the machine M1, continuously emulsifying by rotor speed 10000 rpm, and obtained an emulsification coagulant (tofu coagulant). Coagulation dispersion machine M1 is manufactured by PRIMIX Corporation, named Homo-mixer Mark 2-40 type. Curding machine is batch type and manufactured by Takai Tofu & Soymilk Equipment Co., named Mini-Curdy. Use the tofu coagulant producing apparatus N1 according to the first embodiment. A cooling mean R is addition to Milder jacket (as shown in FIG. 1 symbol R) and cooling water temperature is 10 deg C. (preferably 0 to 5 deg C.).

For tofu curding action, prepare soymilk for silken tofu 13% brix, temperature 80 deg C., 12 liter input flat box. The tofu coagulant amount, concentration of magnesium chloride solution that converted to magnesium chloride (hexahydrate) weight 2.8 g for soymilk 1 liter. The emulsified tofu coagulant within 60 minutes after emulsifying and dispersion, is input the soymilk and stirred and dispersed about 20 seconds by coagulation dispersion machine M2 that rotation speed 2000 rpm, and make a tofu. To aged, wait 30 minutes after made the tofu, and evaluate the tofu checking by visual, touching and eating. See table 1. As the result, example 1-1, example 1-3 are produced a smooth pudding-like silken tofu. In case of example 1-2 is shorten emulsifying time 0.5 minutes, thus emulsion temperature increase near 30 deg C. by stir heat as friction heat. Therefore, the emulsion was unstable and slightly rough surface of the tofu and emergent. Example 1-1 is used cooling means and suppressed the emulsion temperature after emulsification. Example 1-3 is pre-cooled the fat and suppressed the emulsion temperature after emulsification. The comparative examples, that only Nigari input the soymilk 80 deg C. and stirred and dispersed, is a rough surface weak tofu, so it is not show in table 1.

TABLE 1 Fat Nigari Emulsifying Coagulant Cooling temperature Temperature time Temperature Tofu means (deg C.) (deg C.) (sec.) (deg C.) Evaluation Example 1-1 yes 10.3 19.1 120 22.3 good Example 1-2 no 10.3 19.1 50 29.0 not so good Example 1-3 yes 4.1 3.6 230 19.0 very good

Example 2

Magnesium chloride solution as Nigari that is made by Naikai Salt Industries CO., LTD., that named White-Nigari. Food fat is pure olive oil made by J-OIL MILLS, Inc. Magnesium chloride solution is into freezer, and olive oil is into refrigerator. Temperature of the magnesium chloride solution is −7 deg C., and temperature of the olive oil is 4.2 deg C. Magnesium chloride and water ratio is 2:1, and make a magnesium chloride solution that concentration is 66.7% w/w as density 1.34 and 4.3 M. Pre-mixture the magnesium chloride solution 500 g and olive oil 500 g separately, and sending each material to an emulsifying dispersion machine M1 and make a tofu coagulant. Emulsifying dispersion machine M1 is manufactured by Pacific Machinery & Engineering Co., Ltd., named Milder for laboratory. Machine M1 rotor speed is 10000 rpm and squeezing out put valve and continuously emulsifying and dispersion, and make the tofu coagulant. The concentration of magnesium chloride in solution is about 33% wt, density is about 1.1.

The second example, uses the soymilk coagulation machine Z3 with one-way continuous pathway comprising the tofu coagulant producing apparatus N6. Temperature in the system that was judged to be good emulsified state at the time of the emulsifying dispersion machine M1 is stopped. Cooling means R is not arranged. For tofu curding action, prepare soymilk for Kinugoshi (silken) tofu 13% brix, temperature 80 deg C. and continuously flow, and addition the tofu coagulant after made within 5 or 60 minutes. The tofu coagulant amount, concentration of magnesium chloride solution that converted to magnesium chloride hexahydrate weight 2.5 g for soymilk 1 liter. The soymilk flow 200, 300 and 420 liter/hour, the tofu coagulant 1.36, 2.05, 2.86 liter/hour, and receive it to a box as 3 liters, and check the product slow-acting time by visual. Slow-acting time is between into the box and beginning to curd. To aged, wait 30 minutes after made the tofu, and cut out to cylindrical tofu that diameter 20 min and height 20 mm, and set it on Rheometer, and evaluate the tofu hardness. Rheometer is manufactured by Fudo Engineering Co., Ltd., named NRM-2002J and plunger diameter 20 mm, sample table rising speed 60 mm/minute. And evaluate the tofu checking hardness (shear force), distortion, crisp tasting, whether the appearance of a smooth Kinugoshi tofu. See table 2. As the result, example 2-2 is produced a smooth pudding-like silken tofu. Example 2-2 as soymilk flow 300 liter/hour is made a most hard tofu. Example 2-1 as soymilk flow 200 liter/hour is made a little soft tofu. Example 2-3 as soymilk flow 420 liter/hour is made a little rough surface tofu.

TABLE 2 Fat Nigari Slow-acting Tofu Tofu flow temperature Temperature time hardness Tofu (Liter/hour) (deg C.) (deg C.) (sec.) (×10² N/m²) Evaluation Example 2-1 200 4.1 −7 30.0 81.1 good Example 2-2 300 4.1 −7 12.3 89.2 very good Example 2-3 420 4.1 −7 5.4 83.7 good

Example 3

Magnesium chloride solution as Nigari that is made by Naikai Salt Industries CO., LTD., that named White-Nigari. Food fat is selected one of the, cone oil (made by Boso oil and fat CO., LTD.) and palm oil (made by Fuji oil CO., LTD.) mixtures ratio 1:1, soybean oil (made by J-OIL MILLS), rice oil (made by J-OIL MILLS), cone oil (made by Boso oil and fat CO., LTD.), rapeseed oil (made by J-OIL MILLS). Temperature of Nigari is 13 deg C., and each temperature of the oil is 13 deg C., and produced the emulsification coagulant as example 2. A machine for soymilk coagulation, comprising the tofu coagulant producing apparatus uses as second embodiment. An emulsifying dispersion machine M1 rotation speed is 2000 rpm that is same as example 1.

For tofu cording action, prepare soymilk for silken tofu 13% brix, temperature 80 deg C. and continuously flow. The tofu coagulant amount, concentration of magnesium chloride solution that converted to magnesium chloride hexahydrate weight 2.8 g for soymilk 1 liter, and receive it to a box as 3 liters, and check the product slow-acting time by visual. Slow-acting time is between into the box and beginning to curd. To aged, wait 30 minutes after made the tofu, and cut out to cylindrical tofu that diameter 20 mm and height 20 mm, and set it on Rheometer, and evaluate the tofu hardness. Rheometer is manufactured by Fudo Engineering Co., Ltd., named NRM-2002J and plunger diameter 23 mm, sample table rising speed 60 mm/minute. And evaluate the tofu checking hardness (shear force), distortion, crisp tasting, whether the appearance of a smooth Kinugoshi tofu. Checking inside, and eating. See table 3.

As the result, example 3-2 uses as soybean oil is acceptable, made a smooth and hard tofu, but slow-acting time is shorten and little weak. Because, content of soybean oil DAG is rather smaller than the cone oil DAG and palm oil DAG Example 3-3, example 3-4 and example 3-5 are produced a smooth and hard tofu, and cone oil, rice oil, rapeseed oil each is able to prepare the emulsified tofu coagulant. As the result, example 3-1 uses as mixtures cone oil and palm oil, slow acting time is enough, and made a smooth tofu, but hardness is not enough a little. Cone oil and palm oil comprise DAG relatively high and low cost. Palm oil has slow-acting character and high melting point. Thus, palm oil and cone oil mixtures ratio is between 1:1 and 1:10, is obtained liquid food fat, and easy to handling, made a smooth and hard tofu.

TABLE 3 Fat and Nigari Slow-acting Tofu Fat temperature time hardness Tofu (oil type) (deg C.) (sec.) (×10² N/m²) Evaluation Example 3-1 Cone and Palm 13 40 47.1 very good Example 3-2 Soybean 13 15 52.9 good Example 3-3 Rapeseed 13 30 45.1 good Example 3-4 Cone 13 25 48.0 good Example 3-5 Rice 13 30 58.8 good

Example 3-2 uses soybean oil, soymilk coagulation slow-acting, although the emulsion coagulant could not remain long, only about one minute. Soybean oil including DAG is smaller than corn oil and palm oil that is reason, considered.

Example 4

Table 4 (table 4-1, table 4-2 and table 4-3) shows emulsion easiness that how easy to W/O emulsion after emulsifying dispersion, emulsion stability that how keep W/O emulsion during warms 45 deg C. Emulsifying dispersion machine is used such a batch type as shown in FIG. 3. Coagulation dispersion machine M2 is manufactured by Yamato Scientific Co., Ltd, named Ultra-disperser LK-22 with generator shaft: S-25N-10 G, and it rotation speed is 20,000 rpm. Stir the fat 50 g and added 4M magnesium chloride 50 g and emulsifying 3 minutes.

As shown in table 4, correlation between DAG content and emulsion easiness is high, and correlation between DAG content and emulsion stability is high. But, correlation between MAG content and emulsion easiness is low, and correlation between MAG content and emulsion stability is low. DAG content is depended on oil material, oil expression and purification. Thus, same material but DAG content is different. In the table 4, comprises DAG between 1 and 10%. The invention, the food, fat is a plant-derived ingredient and comprising phospholipid is 0.1% or less. According to palm oil, cone oil and pure olive oil, warms 45 deg C. and 120 minutes and confirms emulsion stability. Virgin olive oil, soybean oil and palm oil are rather unstable. Macadamia-nut oil, Safflower oil, Perrila Oil can't confirms emulsion stability. If use tofu curding system Z2 with one-way continuous path and cooling means R1 and R2 attached, those Macadamia-nut oil, Safflower oil, Perrila Oil will be reach more stable emulsion. Only DAG is a good correlation with emulsion easiness or emulsion stability, as shown in table 4. Those phospholipid, MAG and free fatty acid are almost rejected de-gumming and de-acidification wintering at purified process. As Japanese Agricultural Standards, acid value most of the food fat is 0.2 or less. Sesame oil acid value is 4 or less, and Olive oil acid value is 2 or less. The invention, food fat means food plant oil or food processing oil specified Japanese Agricultural Standards or same Standards. Table 4 shows a part of food fats applicable to the invention. Therefore, the food fat is not limited and it can be use meet the conditions of the invention.

Table 4 (table 4-1, table 4-2 and table 4-3) shows characteristics of plant oils. Emulsion easiness (*a) is how easy to W/O emulsion after emulsifying dispersion on batch test, and scale with 10 points. Emulsion stability (*b) is how keep W/O emulsion during warms 45 deg C. on batch test, and scale with 10 points. Free fatty acid value (*c) is calculated that is ((acid value/56)×(average molecular weight−38)/3/1000)×100. Saturated fatty acid (*d) and Double bond (*d) are calculated fatty acid composition. MAG (*1), DAG (*1) and TAG (*1) are analyzing result of Japan institute of oil & fats, other foods inspection foundation. DAG literature (*2) is cited R. P. D′alonzo, W. J. Kozarek and R. L. Wade: J. Am. Oil Chem. Soc., 59, 292, Year 1982, Journal of the American Oil Chemists' Society. Acid value (*3) is measured by Takai Tofu & Soymilk Equipment Co., Viscosity (*4) is measured by Takai Tofu & Soymilk Equipment Co., and used B type viscosity meter with BL adapter.

TABLE 4-1 Palm Cone Pure Virgin oil oil olive oil olive oil Emulsion easiness (*a) 7 5 5 3 Emulsion stability (*b) min. 120 120 120 60 MAG (*1) % 0.2 0.8 1.0 0.4 DAG measured (*1) % 7.5 5.2 5.4 3.6 DAG literature (*2) % 5.8 2.8 5.5 5.5 TAG (*1) % 92.7 94.4 94.4 94.9 Acid value (*3) 0.11 0.13 0.18 0.76 Fatty acid value (*c) % 0.05 0.05 0.09 0.38 Saturated fatty acid (*d) % 50.7 14.3 14.2 14.2 Double bond (*d) % 1.8 4.0 2.8 2.8 Viscosity at room (*4) mPa · s 70 52 62 — Viscosity at mPa · s — 108 133 133 10 deg C. (*4) Slow-acting character very very very good good good good

TABLE 4-2 Rice Cotton Peanut Soybean oil seed oil oil oil Emulsion easiness (*a) 7 7 2 2 Emulsion stability (*b) min. 120 20 90 20 MAG (*1) % 0.4 0.3 0.5 0.4 DAG measured (*1) % 9.9 7.8 3.6 3.2 DAG literature (*2) % — 3.1 2.2 1.0 TAG (*1) % 89.7 91.3 95.7 97.2 Acid value (*3) 0.16 0.12 0.20 0.10 Fatty acid value (*c) % 0.08 0.06 0.10 0.05 Saturated fatty % 21.6 26.2 13.4 14.7 acid (*d) Double bond (*d) % 3.6 3.9 3.6 4.6 Viscosity at room (*4) mPa · s 73 55 72 49 Viscosity at mPa · s 133 114 122 100 10 deg C. (*4) Slow-acting character good good not so not so good good

TABLE 4-3 Coconut Rapeseed Macadamia Safflower oil oil nut oil oil Emulsion easiness (*a) 2 2 0 0 Emulsion stability (*b) min. 20 60 0 0 MAG (*1) % 0.5 0.4 0.3 0.4 DAG measured (*1) % 2.5 3.2 2.2 2.4 DAG literature (*2) % 2.2 — — 2.1 TAG (*1) % 97.2 96.1 97.5 96.6 Acid value (*3) 0.11 0.12 0.06 0.08 Fatty acid value (*c) % 0.04 0.06 0.03 0.04 Saturated fatty acid (*d) % 30.4 26.2 10.3 11.3 Double bond (*d) % 0.3 3.9 2.6 4.9 Viscosity at room (*4) mPa · s 52 55 73 55 Viscosity at 10 deg C. (*4) mPa · s — 117 135 129 Slow-acting character not so good not so good bad bad

Example 5

To study relation between mineral salt concentration and tofu quality included coagulant cost, is as shown in table 5 (table 5-1 and table 5-2). Use the tofu curding system Z1 with one-way continuous path as shown in FIG. 1. Particularly, use the tofu curding system Z2 with one-way continuous path and cooling means R1 and R2 attached as shown in FIG. 2. It is effective suppressed stirring heat up and keeping emulsion stable. In each example shown in Table 5, Nigari (magnesium chloride) and calcium chloride is “Sofutoueha” “Karumeit” (both Ako chemical Co.), using vegetable oil as olive, safflower oil (both J OIL Co. made) was used. The cooling means is used jacket tank (T1, T2) onto material tank, and refrigerant for cold water at 10 deg C., and about the temperature of the each liquid raw material 15 deg C. Back-pressure means V1, V2 are arranged on the each feedback pathway, and adjust to 0.1 MPa. Emulsifying dispersion machine M1 is manufactured by Pacific Machinery & Engineering Co., Ltd., named Milder for laboratory, with jacket tank and cooling water temperature is 10 deg C. Using 8,000 rpm rotational speed emulsion dispersion performed, and back pressure valve V3 is arranged onto output and adjust inner pressure 0.1 MPa. Soymilk flow metering pump P3 by 40 l/minute, whereas the liquid feed, the amount of calcium chloride 0.2%, or magnesium chloride 0.3%, and the ratio of liquid food oil and mineral salt solution be as shown in Table 5, adjusting by each metering pump P1, P2. For example 5-1 in the table 5, mineral salt solution (2M magnesium chloride) to 324 g/min, cooking oil (olive oil) to 324 g/min pumping to the emulsifying dispersion machine M1. Other conditions were same. Emulsifying dispersion machine M1 emulsion coagulant was obtained from 648 g/min soymilk is supplied to the emulsifying dispersion machine M2 by in line (pipe line), and use the emulsifying dispersion machine M2 (manufactured by PRIMIX Corporation, TK pipeline homo-mixer), using a 2,000 rpm rotational speed distributed spreading, dispersing the emulsion coagulant into the soymilk, and receive a box for about 15 seconds, as about 10 liters soymilk, and made a prototype soft tofu be aged to stand for 30 minutes.

As a result, Example 5-1, Example 5-2 in the manufacture of soft tofu is smooth and beautiful skin like a pudding. Comparative Example 5-2, as conditions in the dense emulsion of liquid coagulant safflower oil are unstable, a rough cut surface of tofu became more water. Example 5-4 emulsified state was unstable even at low volume as cooking oil.

TABLE 5-1 Comparative Example Example Comparative 5-1 5-1 5-2 5-2 Mineral salt 1M 2M 4M 4M solution MgCl₂ MgCl₂ MgCl₂ MgCl₂ Food fat Olive oil Olive oil Olive oil Safflower oil Water phase:Oil 1:1 1:1 1:1 1:1 phase ratio Emulsion stability very good very good good NG at 45 deg C. separated few minutes Slow-acting very good very good very good NG character Tofu condition soft a little soft hard weak, emergent Cost of coagulant too high a little high half cost half cost NG OK OK OK

TABLE 5-2 Example Example Comparative 5-3 5-4 5-3 Mineral salt solution 4M 2M 4M CaCl₂ MgCl₂ MgCl₂ Food fat Olive oil Olive oil Olive oil Water phase:Oil phase ratio 1:1 1:0.2 1:3.5 Emulsion stability at 45 deg C. good good very good separated 1 hour Slow-acting character very good good very good Tofu condition hard hard a little soft oily smell Cost of coagulant half cost half cost too high OK OK NG

Actually, the water phase and the oil phase ratio is between 1:0.5 and 1:1.5 that is economical cost range. In case of the oil phase is smaller, emulsion is unstable and slow-acting character is low. In case of the oil phase is bigger, addition amount to tofu is increased and cost is getting high.

The invention of tofu coagulant, the concentration of magnesium chloride is 2 M or more. The dense magnesium chloride concentration between 3 and 5 M, is preferably, and upper limit is 6.1 M or under. Saturated aqueous solution of magnesium chloride is 4.8 M at 10 deg C., 5 M at 40 deg C., 5.6 Mat 80 deg C., 6.1 Mat 100 deg C., for example. Magnesium chloride 6.1 M is maximum, cause 100 deg C. is upper limit. Saturated aqueous solution of magnesium sulfate is 3.8 M maximum, and calcium chloride is 8.8 M maximum. It can be use the tofu coagulant which water phase is even if cloudy or part of solidify. Also, it can be use the tofu coagulant which oil phase is slurry such a calcium sulfate particles included. But it is not useful, because the emulsified tofu coagulant unstable and pump and pipe are affected deposition of the oil phase.

Practically, it is necessary to increase oil phase (continuous phase) as water phase (disperse phase) amount. Thus, decreasing water phase and suppressing the oil phase volume that is advantageously to cost reduction. Moreover, increasing the concentration of magnesium chloride in the water phase, fewer usages to the coagulant and possibly reaches more cost reduction. Study to W/O type emulsion characteristic that is used 0.5M magnesium chloride solution and processing oil and does not use additives as emulsifiers, is disclosed in prior art document 2. Refer FIG. 1 of prior art document 2, dense magnesium chloride and dense calcium chloride is unstable, estimation, but, emulsion is stable cause of emulsion viscosity increasing. Dense mineral salt solution is specially damaged heat up by stirring heat and dissociation effect. Therefore, in the invention, uses one-way continuous path and cooling means at system Z2. Most of commercial magnesium chloride seawater crude is 2 M or more. Concentration 2M is sum of magnesium chloride mol, magnesium sulfate mol, calcium chloride mol and calcium sulfate mol in solution 1 liter.

The present invention of a method for producing tofu coagulant, wherein interfacial tension of the food fat against distilled water is 34 mN/m or less at room temperature. The water phase as magnesium chloride and the oil phase such olive oil and rice bran oil are stirred and mixed to W/O type emulsion. DAG interfacial tension is low, and the content of DAG effect to total food fat interfacial tension to decrease, and emulsion is stabilized by the action of surface-active phase. TAG and DAG interfacial tension is cited prior art document 3. However, relation between DAG content and food fat interfacial tension is not disclosed. Moreover, about W/O type emulsion, relation between mineral salt solution as Nigari and DAG content of food fat is not disclosed.

Example 6

For about typically food fat, measure the interfacial tension at room temperature. Test equipment is manufactured Kycwa Interface Science Co., ltd. named DropMaster DM301. Perrila oil and macadamia-nut oil are sample that is difficult emulsifying. Table 6 shows characteristics of plant oils. Processing oil* is commercial processing oil include DAG highly. Emulsion easiness (*a) is how easy to W/O emulsion after emulsifying dispersion on batch test, and scale with 10 points. Emulsion stability (*b) is how keep W/O emulsion during warms 45 deg C. on batch test, and scale with 10 points.

TABLE 6 Compar- Compar- ative Comparative Example Example ative 6-1 6-2 6-1 6-2 6-3 Food fat Perrila Macadamia- Soybean Cone Processing oil nut oil oil oil oil* Interfacial 34.2 29.2 32.5 26.1 12.5 tension (mN/m) Emulsion 0 0 2 5 10 easiness (*a) Emulsion 0 0 2 10 10 stability (*b) DAG 3.6 2.2 3.2 5.2 87.1 (%)

As shown in table 6, when the interfacial tension at room temperature over the 34 mN/N, difficult to emulsion and unstable. In the invention, the interfacial tension at room temperature is 34 mN/m or less, particularly the interfacial tension 30 mN/m or less, which is easy obtained W/O type emulsion and stable condition. See table 6. As comparative 6-1, Perrila oil interfacial tension is 34.2 mN/m that why Perrila oil couldn't to be emulsion. As example 6-1, Soybean oil interfacial tension is 32.5 mN/m that why Soybean oil could be emulsion. Perrila oil DAG content is 3.6%, and Soybean oil DAG content is 3.2%. Therefore, according emulsification, the interfacial tension is more effective than DAG content. On the other hand, Macadamia-nut oil DAG is 2.2%, and Soybean oil DAG content is 3.2%. In case of it, as comparative 6-2, Macadamia-nut oil DAG is 2.2% that why Macadamia-nut oil couldn't to be emulsion. If a surface-active agent into the emulsifier, the interfacial tension is below 10 mN/m. Therefore, according to the invention, wherein interfacial tension of the food fat against distilled water is between 10 and 34 mN/m at room temperature, and particularly the interfacial tension is between 10 and 30 mN/m. The food fat as oil phase including. DAG is 1 wt % or more, and particularly DAG is 3 wt % or more, and/or, the interfacial tension is between 10 and 34 mN/m, and particularly the interfacial tension is between 10 and 30 mN/m. Refer to such Cone oil DAG 5.2% and interfacial tension 26.1, or Soybean oil DAG 3.2% and interfacial tension 32.5, or Processing oil DAG 87.1% and interfacial tension 12.5. See table 6. The food fat interfacial tension is decreased when temperature is increased. In case of it, advantageous to emulsify, but emulsion viscosity is decreased and doing to re-aggregate and unstable emulsified phase. In case of the interfacial tension of the food fat is between 10 and 34 mN/m and DAG is less than 1 wt % that is difficult to emulsify and unstable.

The invention of tofu coagulant, water phase size (diameter) average is between 0.01 and 100 micro meter, average between 1 and 10 micrometer is preferably, average between 1 and 5 micrometer is more preferably. According to the present invention, when the water phase size average is bigger than criteria, emulsification is unstable. In opposition, when the water phase size average is smaller than criteria, emulsification viscosity is increased and difficult to measure and difficult to disperse in soymilk and cause of coagulating irregular. To measure on flow meter the water phase diameter, put the emulsion on glass plate and put cover glass on it and immediately view and photo by digital microscope (manufactured by Keyence Corporation named VHX-500F, and high-resolution lens VH-Z500W) by transmission shooting, after that measure particle diameters in photos 100 micrometer square area, and measure particle diameter by compass and calculate average diameter, median diameter and standard deviation. The water phase size is able to control by food fat, temperature and machine conditions. When the water phase size is smaller, coagulation slow-acting effect is up. In opposition, when the water phase size is bigger, coagulation slow-acting effect is down. As above embodiments, the soymilk temperature is between 0 and 99 deg C., the temperature between 60 and 95 deg C. is preferably, and the temperature between 75 and 85 deg C. is practical and more preferably.

As above embodiments, describe producing method for silken tofu. The scope of the invention, as well as silken tofu, kinugoshi-tofu, momen-tofu, namaage-tofu, atuage-tofu, can utilize a variety of tofu products. 

1. An apparatus for producing tofu coagulant, comprising: a liquid food oil pumping pathway from a liquid food oil tank by a metering pump; a mineral salt solution pumping pathway from a mineral salt solution tank by another metering pump; an emulsion dispersion machine for stirring the liquid food oil with the mineral salt solution to an emulsification phase; wherein the liquid food oil pumping pathway is connected with the mineral salt solution pumping pathway, and the mineral salt solution is added predetermined ratio for producing the tofu coagulant, wherein the water phase and the oil phase are stirred and mixed to W/O type (water in oil type) emulsion (without emulsifier).
 2. An apparatus for producing tofu coagulant according to claim 1, wherein the mineral salt solution pumping pathways are cascaded, and the mineral salt solution is added multiple.
 3. An apparatus for producing tofu coagulant according to claim 1, further comprising a cooling unit is arranged to the liquid food oil pumping pathway and/or the mineral salt solution pumping pathway.
 4. An apparatus for producing tofu coagulant according to claim 1, further comprising a cooling unit is arranged to the emulsion dispersion machine and/or a pressing unit is arranged to the emulsion dispersion machine.
 5. An apparatus for producing tofu coagulant according to claim 1, further comprising a flow-meter with indicating controller for control discharge rate of the metering pump is arranged to the liquid food oil pumping pathway and/or another flow-meter with indicating controller for control discharge rate of the another metering pump is arranged to the mineral salt solution pumping pathway.
 6. An apparatus for producing tofu coagulant according to claim 1, further comprising a feedback pathway is arranged to the liquid food oil pumping pathway and/or a feedback pathway is arranged to the mineral salt solution pumping pathway, and wherein a back-pressure means is arranged on each of the feedback pathway.
 7. A machine for soymilk coagulation, comprising the tofu coagulant producing apparatus according to claim 1, and further comprising: a produced tofu coagulant pumping pathway from the emulsion dispersion machine; a soymilk pumping pathway from a soymilk tank by a metering pump; wherein the produced tofu coagulant pumping pathway is connected with the soymilk pumping pathway, and both the pathways are connected to a dispersion machine for stirring the soymilk with the tofu coagulant.
 8. A machine for soymilk coagulation, comprising the tofu coagulant producing apparatus according to claim 1, and further comprising: a produced tofu coagulant pumping pathway from a tofu coagulant tank by a metering pump; a soymilk pumping pathway from a soymilk tank by another metering pump; wherein the produced tofu coagulant pumping pathway is connected with the soymilk pumping pathway, and both the pathways are connected to a dispersion machine for stirring the soymilk with the tofu coagulant. 